JAMB Mathematics Past Questions & Answers - Page 227

1,131.

A train moves from P to Q at an average speed of 90km/h and immediately returns from Q to P through the same route at an average speed of 45km/h. Find the average speed for the entire journey

A.

55.00km/h

B.

60.00km/h

C.

67.50km\h

D.

75.00km\h

Correct answer is C

Average speed from P to Q = 90km\h

Average speed from O to P = 45km/h

Average for the entire journey = 90 + 45

\(\frac{135}{2}\) = 67.50 km/h

1,132.

Reduce each number to two significant figures and then evaluate \(\frac{0.021741 \times 1.2047}{0.023789}\)

A.

0.8

B.

0.9

C.

1.1

D.

1.2

Correct answer is C

\(\frac{0.021741 \times 1.2047}{0.023789}\) = \(\frac{0.022 \times 1.2}{0.024}\) (to 216)

= \(\frac{0.0264}{0.024}\)

= 1.1

1,133.

A rectangular lawn has an area of 1815 square yards. if its length is 50 meters, find its width in meters given that 1 metre equals 1.1 yards

A.

39.93

B.

35.00

C.

33.00

D.

30.00

Correct answer is D

1m = 1.1 yard, length(L)= 50m

= (50 x 1.1)yards

= 55 yards

Area(A) = length(L) y width (W)

1815 = 55y width (W)

width (w) = \(\frac{1815}{55}\)

= 33 yards

But 33 yards = 30 meters

1,134.

Find the least length of a rod which can be cut into exactly equal strips, each of either 40cm or 48cm in length

A.

120cm

B.

240cm

C.

360cm

D.

480cm

Correct answer is B

The least length is \(\frac{40}{48}\) = \(\frac{5}{8}\)

for the rod to be cut in exactly equal trips

Ratio \(\frac{5}{6}\) : \(\frac{48}{40}\)

\(\frac{\frac{5}{6}}{\frac{40}{48}}\) = 1

\(\frac{5}{6}\) x \(\frac{48}{40}\) = \(\frac{240}{240}\) = 1

The least length = 240cm

1,135.

Convert 241 in base 5 to base 8,

A.

718

B.

1078

C.

1768

D.

2418

Correct answer is B

2415 = 2 x 52 + 4 x 5 + 1 x 5 + 1 x 5o

50 + 20 + 1 = 7110

Convert 7110 to base 8
\(\begin{array}{c|c} 8 & 71 \\ 8 & 8 R 7\\8 & 1 R 0\\8 & 0 R 1\end{array}\)

= 1078